The semiconductor characteristics of anatase TiO2(001) films, which were pulsed laser-deposited on a 0.05 wt % Nb-doped SrTiO3(001) single crystal electrode, as well as the film/electrolyte heterointerfaces were investigated by the ultrahigh-vacuum electrochemistry approach. In addition to the current-voltage measurements, equivalent circuit modeling in electrochemical impedance spectroscopy at different electrode potentials reveals that the flat band potential of anatase TiO2 films shifts by +0.5 V when the film thickness increases with (1 × 4) surface reconstruction more visible in reflection high energy electron diffraction. The possible origins of the observed flat band potential shift will be discussed from the viewpoint of electric double layer effects, mainly of donor-type surface states and surface reconstruction, compared with the results of single crystal rutile TiO2(110).
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films